<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
      .box{
          overflow: hidden;
          width: 100px;
          height: 100px;
          background-color: green;
          margin: 200px auto;
          
      }
      .box::after{
          content: "Bilibili";
          display: block;
          width: 100px;
          height: 100px;
          background-color: yellowgreen;
          transform:rotate(180deg);
          transform-origin: center bottom;
          transition: all 1s;
      }
      .box:hover::after{
          transform: rotate(360deg);
      }
    </style>
</head>
<body>
     <div class="box"></div>
</body>
</html>